Testosterone
More than a sex hormone. Testosterone affects muscle, bone, brain, mood, and metabolism. Essential for men and important for women too. Declining levels drive many aging symptoms.
⚡ What Testosterone Does
Muscle Mass
Promotes protein synthesis and muscle growth
Bone Density
Maintains bone strength and prevents osteoporosis
Mood/Cognition
Affects confidence, motivation, and mental clarity
Libido
Primary driver of sex drive in both sexes
Fat Distribution
Promotes lean body composition
Red Blood Cells
Stimulates erythropoiesis in bone marrow
🔄 Testosterone Pathways
5α-Reductase → DHT
Converts testosterone to dihydrotestosterone (DHT). More potent, affects prostate, hair follicles. 5α-reductase inhibitors block this.
Aromatase → Estrogen
Converts testosterone to estradiol. Happens in fat tissue. More body fat = more conversion. Aromatase inhibitors block this.
Total testosterone tells part of the story. Free testosterone (not bound to SHBG) is the active form.
🔻 Signs of Low Testosterone
Physical
- • Muscle loss
- • Increased body fat
- • Fatigue
- • Reduced strength
Sexual
- • Low libido
- • Erectile dysfunction
- • Reduced spontaneous erections
Mental/Emotional
- • Depression
- • Low motivation
- • Brain fog
- • Irritability
Metabolic
- • Insulin resistance
- • Increased visceral fat
- • Metabolic syndrome
Other
- • Sleep problems
- • Hot flashes
- • Bone loss
Women (Low T)
- • Low libido
- • Fatigue
- • Muscle weakness
⚠️ What Lowers Testosterone
Lifestyle
- • Chronic stress (cortisol)
- • Poor sleep
- • Obesity (aromatization)
- • Sedentary lifestyle
- • Excess alcohol
Nutritional
- • Zinc deficiency
- • Vitamin D deficiency
- • Low cholesterol (precursor)
- • Low calorie diets
- • Low fat diets
Environmental
- • Endocrine disruptors (BPA, phthalates)
- • Pesticides
- • Plastics
Medical
- • Opioid medications
- • Certain antidepressants
- • Statins (some)
- • Diabetes/insulin resistance
✅ Supporting Healthy Testosterone
Resistance Training
Compound lifts acutely boost testosterone
Quality Sleep
Most testosterone made during sleep
Reduce Body Fat
Less aromatization to estrogen
Zinc
Essential for production and conversion
Vitamin D
Optimal levels support testosterone
Manage Stress
High cortisol suppresses testosterone
Magnesium
Supports production and free T levels
Healthy Fats
Cholesterol is the precursor
Boron
May increase free testosterone
🧪 Testing Testosterone
Total Testosterone
All testosterone in blood (bound + free). Test in AM when levels peak. Normal: 300-1000 ng/dL.
Free Testosterone
The active, unbound fraction (~1-2%). More clinically relevant. Can be measured directly or calculated.
SHBG
Sex hormone binding globulin. High SHBG = less free T. Affected by age, thyroid, liver, estrogen.
Also Consider
LH, FSH (pituitary function), estradiol, DHT, prolactin for full picture.
Metabolic Connections
Zinc
Required for testosterone production and preventing conversion to estrogen
Vitamin D
Low D correlates with low testosterone
Cortisol
High cortisol suppresses testosterone production
Estrogen
Testosterone converts to estrogen via aromatase
Magnesium
Supports testosterone production and free testosterone levels
Insulin
Insulin resistance lowers testosterone